A fuel supply system of a gaseous fuel internal combustion engine includes multiple components including, but not limited to, double-walled connecting elements, double-walled fuel supply line elements and valves. The double-walled fuel supply line elements and connecting elements include an inner line element for receiving a gaseous fuel therethrough. As the gaseous fuel flows through the inner line element, there may be possibilities that the gaseous fuel leak out through the inner line element. To prevent the gaseous fuel from spreading to the ambient atmosphere, an outer line element is provided around the inner line element. The outer line element and the inner line element define a fuel leak detection space to receive the gaseous fuel coming out of the inner line element. Moreover, the fuel supply system is provided with a valve that is fluidly communicated between an inert gas supply line and the double-walled fuel supply line elements. The valve is configured to selectively purge the whole fuel supply system with an inert gas.
The valve also includes an inner body for selectively communicating between the inert gas supply line and the double-walled fuel supply line elements. An outer body is disposed around the inner body to define a fuel leak detection space. The leak detection space of the valve further communicates with the leak detection space of the fuel supply system. However, designing and manufacturing such double-walled valve is complex.